1. Field of the Invention
The present invention relates to a substrate processing method and a substrate processing apparatus for processing substrates. Examples of substrates to be processed include semiconductor wafers, substrates for liquid crystal displays, substrates for plasma displays, substrates for FEDs (Field Emission Displays), substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks, substrates for photomasks, ceramic substrates, and substrates for solar cells.
2. Description of Related Art
In steps of manufacturing a semiconductor device, a front surface of a substrate, such as a semiconductor wafer, is processed by a processing liquid. A single substrate processing type apparatus that processes substrates one by one includes a spin chuck that rotates a substrate while holding the substrate substantially horizontally and a nozzle that supplies a processing liquid to the front surface of the substrate rotated by the spin chuck.
In a typical substrate processing step, a chemical liquid is supplied to the substrate held by the spin chuck. Thereafter, a rinsing liquid is supplied to the substrate, and, as a result, the chemical liquid on the substrate is replaced with the rinsing liquid. Thereafter, a spin drying step to exclude the rinsing liquid on the substrate is performed. In the spin drying step, the substrate is rotated at a high speed, and, as a result, the rinsing liquid adhering to the substrate is spun off and is removed (dried). A generally-used rinsing liquid is deionized water.
If a fine pattern is formed on the front surface of the substrate, there is a fear that it will be impossible to remove the rinsing liquid that has entered the inside of the pattern in the spin drying step, and hence there is a fear that defects in drying will occur. Therefore, as is disclosed by U.S. Pat. No. 5,882,433 A, a technique has been proposed in which an organic solvent liquid, such as isopropyl alcohol (IPA), is supplied to the front surface of the substrate that has already been processed by the rinsing liquid, and then the front surface of the substrate is dried by replacing the rinsing liquid that has entered gaps of the pattern of the front surface of the substrate with the organic solvent liquid.